A comparison of the rates of ozonation of biological antioxidants and oleate and linoleate esters

The rates of reaction with ozone of some biological antioxidants and simple polyunsaturated fatty acids (PUFA) have been measured in water or in aqueous micellar solutions. At pH 7.0 the rate constants are ca . 10 6 M −1sec −1 for urate, alpha-tocopherol, and PUFA, and 6 × 10 7 M −1sec −1 for ascorbate. When ozone-containing air is breathed, ascorbate in the lung may undergo direct ozonation. However, alpha-tocopherol is probably spared direct reaction with ozone because it doesn't effectively compete with PUFA in pulmonary membranes; rather, tocopherol is used to scavenge radicals produced from the ozone-PUFA reaction.